Steam heating system



Oct. 11, 1949.

E. P. HARRISON STEAM HEATING SYSTEM Filed Deo. 23, 1946 Hrrsa/z The steam heating system representeddia K grammatically in Fig. l includes a boiler i6; a

high pressure steam headerII supplied with live steam by the boiler, a return header l2 on' vthe '2.5:

lower pressure side of the system, and ja receiver.

I3 to collect condensate from the return header I2. quired by a boiler pump I5, the boiler pump being,r connected on its intakel side with the'V receiver I3 by a pipe IS, and being connected on its output side with the boiler by a pipe I'I. New water for the system is supplied to receiver I3 as required through a pipe line I 8.

The steam system represented by Fig. 1 has' The steam pipe 36 is provided with a suitable valve 4| and leads to what may be termed a low pressure supply pipe 42. Preferably a steam pipe 43 from the low pressure steam header 28 also leads to the low pressure supply pipe 42, the steam pipe 43 being equipped with a valve 44. A high pressure supplypipe45 extends from the previously mentioned steam header I| to the region of the low pressure supply pipe 42, so that :both the high pressure supply pipe 45 and the low pressure supply pipe 42 may be utilized to satisfy an outside demand.

rThe outsidegdemand for steam in the illustratedA arrangement is provided by a steam shower ors'team spray 41 for moistening a traveling. web of. paper, such steam consuming devices being well known in the art. The steam The boiler I@ is supplied with water as re-' ShOWeI OI Spray 47 S fed by a pipe 3 Controlled by a valve 50. Since the steam should be suppliedfto the pipe 48 in a substantially constant manner, a surge tank* 5| is provided to smooth out. anyluctuations in pressure that may Varise from intermittent or varying release of steam, the releasedsteam being fed into the surge'tank and vbeing fed therefrom to the-pipe'48. The tank 5I also serves as a flash tank. Preferably, but not necessarily, the steam is delivered to thesurgey tank 5I by a suitable injector device 52, the f detailed:'gconstructionof only twelve drier cylinders, there being six drier cylinders I9V in a high pressure bank A andsix drier cylinders in a low pressure'bank B. Actually paper making machinery is,v of course, more elaborate than'in'dicated by Fig. 1. f

striction or orifice fitting 25, that is to say,`a` f fitting orme'ans providing a'restriction to retard the flow of 'steam Yand condensate-from the corresponding drier cylinder to the return line 23, Such Yan orifice member prevents short circuiting or such excessive flow through a drier cylinder as would unduly lower the pressure differential between the' steam header Hand the return line 23. In the particularV arrangement shown' steam and condensate from the return line 23 is conducted through a pipe 26 to a steam separator orY receiver 21 which retains the condensate but vreleases thesteam to a second low pressure steam header 28.

The drier cylinders of the second bankV B have individual supply pipes 3U branching from the low pressure steam -header 28, and have individual discharge pipes 3| that lead'to a common return line 32. Each of the discharge pipes '3| is shown equipped with an orifice fitting 25. Steam and condensate from the second return line 32 is conductedthrough'a pipe 33v to a second steam separator or receiver 35. Condensate is retained' by the receiver 35, but Vany steam therein may escape through a low pressure steam pipe 36.

vEach of the two steam separators or receivers 2'|Y and 35, respectively is provided with a valve 31 controlled by a float 3B so that accumulated condensate may be periodically released fromthe header I2.

which is shown in Fig. 2. The injector device 52 has a jet nozzle 53 fed by the high` pressure supply pipe and has the usual annular portionf55 to which the low pressure supply pipe -42 is connected. The annular portion-narrows to a throat The Varius drier cylinders 59 of bank Afarein the'well known manner, sothat the jet action has a suction effect on the low pressure supply pipe 42. 'Y

The low pressure supply pipe 42 is shown equipped with a check valve 46 to prevent back 'i flow therein, but in some practices of the invention such :a Ycheckvalve .is not necessary. For example, if the pressure.diiTerential-between the steam in the high pressure supply Vpipe 45 andv the low lpressure supply pipe 42 isfrelatively low, or if .the injector device `52 adequately compensatesffor` such a pressure differential,` the check valve 46 may be omitted. Y

Suitable valve means .is` providedv to control the flow of steam through the high pressure supply pipe 45 and the low'pressure supply pipe 42, and to permit varying the ratio of steam flow through the two pipes. Preferably separate valves are employed for the two pipes, the drawing showing a valve 57 controlling flow through the high pressure supply pipel 45 and a second yvalve 58 controlling flow-through the low pressure pipe 42. f v

The high pressure valve 41 is shown equipped with a control arm 6D that it is continuously urged toward open position, by a suitable helical spring 6|. The spring 6| urges the valve arm .againstl avmanually operable adjustment screw 62 that is threaded into `a xed support 63. A

-, suitable solenoid 65 isoperatively connected to the control arm 6U to cause opening movement oi' the arm, and when the solenoid is deenergized ,theV spring 6I moves the valve arm toward closed position.

In like manner the low pressure valve 58 has a control arm 65. that is urged by a suitable spring 67 against an adjustmentscrew 68, the adjustment screw being screw threaded intoa fixed support 69.` A suitable solenoid 'I0 is operatively connected to the valve arm 66 to open casacca the low pressurevalve, the valve armbenlg movedtoward closed position by the spring 'B1 when the solenoid T is -deenerg-ized.

Any suitable means may be 'employed -to 'control the two valve-actuating solenoidsf and it, but I prefer a timer means that will operate ythe two solenoicls'in 'more or less regular cycles. The particular arrangement Shown in Fig. :1 involves the use of' a timer that includes -a rotating disc 12. The disc 12 is made of metal, or at least has 'a metal surface for the conduction Aof current, Iand Ahas on its vface a hearteshaped .plate 13 -of insulating material, the Vsurface 'of the plate "i3 being flush with the face 'o'f the disc. The disc 'l2' is `constantly rotated ley suitable niean's, `such as Va motor l5. The motor 15 maybe ofthe variiabl'e 'speed type controlled by a `suitable rheostat "16. For energization the .motor l is shown connected by two 'wires 1l and :18 to leads 79 'and from a suitablelii. M. source.

A irst brush'Z `iis in contactwith the metal periphery of 'the rotating/'disc 1,2, and a second lbrush '83 'is ymounted on 'a 'carriage Mier moyemen't across Vthe face of th'e 'disc l2 in `a path fdiametrical with respect to the disc. The car- .triage` 8'4 Fis fsliclingiy mounted on a 'guide rod 85 rand is controlled by a suitable worin or 'adjust- 'ment screw 81. The adjustment screw 81 is shown journaled in a xed support T88, is shown provided with a rknurle'd Ahead 89 for vmanual operation.

V'The `described arrangement and shape of the insulating 1p`late"1'3 is such that when the brush 83 is :at the center or axis of rotation of the disc 12 the brush is in constant contact with the insulating plate 13 to prevent current -iiow between the two ybrushes -82 fand l83. On theother hand, when the brush 83 is positioned. near the circumference 4of the rotating disc 1-2 the brush will remain :in `cons-tant contact `with the metal of the disc so that current may flow uninterruptedly between the two brushes 82 'and 33. Between these two fertreme p'esitio'ns of the brush 832is1alrang-e of progressively changing positions which the rctation of the disc causes the path o'f fcond-ucti'on between the vbrush V13:2 and the `brush 28'3 tobe alternately opened and closed 'in repeated cycles. vEach cycle 'has two stages,

one stage of rcurrent o'w, an alternate stage of L.

no Ycur-rent ilow, iand the Vratio 'of time duration of the two stages varies progressively Aas 'the 'brush 783 is shifted 'radially outward. When Vthe brush 353 s relatively nea-r "the axis vvof 'rotation of fthe (disc 'l2 the y'closed 'c'ircui-t periods are relatively short and the open circuit periods are 'relatively long, whereas when the brush 83 is relatively 'close to 'the 'periphery of the `vdisc lf2 the periods 'of current ow are relatively long andthe periods Yo'f decnergizationlarecorrespond- 60 ingly short.

it 'is 'apparent that the rhe'ostat 1S may be adjusted Ato vary the speed of rotation vof the v'disc 'i2 Yand thereby vary `the Vfrequency or dura tion 'of the cycle'sof operation. lt is further apparent that the knurled head :89 vof the adjustment 4screw '137 maybe rotated to vary the relative mations 'of the 'two stages 'in eac-h cycle.

'When the rotating disc l2 provides a path for current conduction 'between the two brushes 82 'and 83 a Solenoid 65 'is energized for opening the high pressure valve 41. The circuit maybe traced as follows: wire "St from 'the previously'mentioned lead 19; the coil of a relay generally designated '9 'I wire 92; 'solenoid "65; 'wire "93; ybrush'8'2';"rr1et'al U gisc l2'; brush 83; `and wire 94 to the second lead The relayV 9| controls ase'cond circuit for en ergizing the second 'solenoid 'It "for the low pressure valve "53, the arrangement 'being such that lsecond circuit 'is open 'when the relay 'is encre d and automatically Acloses 'whenever there- Ylay is deen'ergi'zed. This second valve actuating circuit vmay be traced as follows: wire 96 from the previously mentioned -iead T9; solenoid '10; the armature 0r switch 'arm of relay 9i; and wire '91 'to the second lead tu.

Preferably suitable switches are added to the two circuits to permit flexibility in the modes 'of operation. 'Thus a switch 95 is shown in series with the soieno'id "it for the low 'pressure valve and a shunt controlled by a normally open switch 99, placed vacross the two wires 92 and e3 of the circuit for the solenoid 65 to permit short circuiting oi? that soienoid when desired.

The exceptional flexibility of the described sys#- tein with 'respect to character of operation may be appreciated by considering the following 'ways which the system may be set up for ldifferent modes ai operation in the practice 'of the invention.

First mode of operation In the nist inode of operation the valve M is closed in the steam 'pipe i3 and the valve ii in the steam pipe 35 is opened. Switch 95 is closed and the shunt 'switch 99 i's open. With continuous rotation of the 'timing disc 'l2 the circuit for energizing the solenoid 65 to open the high pressure valve 31 is intermittently energized ySuch energization causes the high pressure valve il to be opened in opposition 'to the spring '6l and simuitaneousiy 'causes the second solenoid 'lil to be-deen'ergized by the relay "9i, thereby to perm-it the second spring tl to close the low pressure valve 5t. During this stage of each cycle of rotation of the disc i2 steam is supplied 'to the surge tank 5|, primarily if not solely, by the high pressure supply pipe t5, the steam flowing directly from the boiler lil without passing through any of the heat exchangers. When the circuit for the soienroid is deen'ergized by the movement of the insulating plate "F3 into position under the brush 83, the spring Si is ffree to close the high pressure valve il and simultaneously the deenergization of the relay 9i causes the circuit to be closed through the second soienoid "lil for opening the low pressure valve 58. During this `second stage of the cycle `of rotation of the disc 12, ksteam supplied to the surge tank 5l, primarily if not solely, by the low pressure supply pipe 32.

It i's to be noted that there is a clear channel from the boiler it through the various drier cylvinders i9 and Z@ to the surge tank el 'since there 'are no traps to block steam iiow. Because such free vcommunication exists between the boier le fand the surge tank 5l by way of the low pressure side of the system, any release yof -steam to the 'surge tank by the low pressure valve e8 will substantially increase the velocity oi iiow through all of th-e drier cylinders riii and 2e, with consequent increase in the heat output of the system. It is to be further noted that the suction effect `of the injector device 52 promotes ow of velocity in the drier cylinders.

Second mode of operation The secondmode of operation is attained by `adjusting either the adjustment screw 62 or the adjustment 'screw S8, or preferably both, the 'setting being such as to prevent complete closing of the corresponding valves. Whenever one of these adjustment screws prevents complete closing of the operation of the corresponding valve, rotation of the disc 12 will result in periodically :changing the rate of ow through the valve. Thus under this second mode of operation there will be continuous but varying iiow through the low pressure valve 58 instead of intermittent now, the flow varying sufficiently to produce the desired pulsating effect in the drier cylinders I9 and 20.

Suppose in this second mode of operation it is desired to increase the rate of steam supply to the steam shower 41 without changing the frequency or quantity of steam released from the low pressure side of the system through the intermittently operated low pressure valve 58. To accomplish this purpose it is merely necessary to change the adjustment of the screw 62 to prevent complete closing of the high pressure valve 41 when the solenoid 65 is deenergized, whereby the total volume of steam supplied from the high pressure side of the system to the high pressure valve 41 will be increased.

Suppose, on the other hand, it is desired that the amount of steam released on the low pressure side of the heating system be varied without substantial change in the overall or average rate of steam supply to the steam shower 41. This purpose may be accomplished by adjusting the screw 58 that limits the closing action of the valve 53 and oppositely adjusting the screw 62 for the valve t1. This second purpose may also be accomplished by introducing adjustment of the screw 81 that determines the position of the brush S3.

Changing the position of the brush 83 will increase or decrease the duration of the periods in which the solenoid is energized, and any furtherV adjustment necessary to avoid Ichanging the total volume of flow to the steam shower 41 may be accomplished by manipulating one or both of the adjustment screws 52 and 68.

Third mode of operation The third mode of operation consists of modifying either of the first two described modes of operation by closing the valve 4I and opening the valve 44. The result of this valve change is to cause the effect of the release of steam through the low pressure valve 58 to be concentrated on the drier cylinders I 9 of the iirst bank A with respect to flow promotion, the second bank of drier .cylinders 2B being cut oi from the effect of releasing steam on the low pressure side of the system.

Fourth mode of operation In the fourth mode of operation the system is set up as described under the rst mode of operation, but the switch 95 is opened to keep the solenoid 1I) deenergized so that the low pressure valve 58 is not responsive to rotation lof the disc 12. The screw 68 associated with the lowpressure valve 58 is adjusted to maintain the valve constantly open to a desired degree, so that steam is continuously released from the return side of the system to the surge tank 5 I. The rotation of the disc 12, however, causes opening and closing of the high pressure valve 6i) in regular cycles, so that high pressure steam from the high pressure supply pipe 45 is intermittently or variably released to the surge tank 5I. During each of the short periods of steam release from the high pressure supply pipe 45 the suction effect of the injector device 52 accelerates ilow through the low pressure supply pipe 42 and causes momentary reduction of pressure in the steam separator 35. Thus the intermittent release of steam from the high pressure supply line 45 results in pulsations in all of the drier rolls I9 and 20 in the heating system.

Fifth mode of operation To change from the fourth mode of :operation described above to the fifth mode of operation the switch 55 is closed and the shunt switch 99 is closed. The closing of the shunt switch 99 shortY circuits the solenoid 55 to make the high pressure valve 4'1 non-responsive to rotation of the timer disc 12, but the closing of the switch make-s the solenoid 1li responsive to the rotation of the disc. It is apparent that the low pressure valve 58 is now opened intermittently to release steam to the surge tank 5I, thereby causing pulsating flow throughout the drier rolls I 9 and 20. The adjustment screw 62 may be positioned to permit the high pressure valve 41 to be constantly closed, or may be positioned to permit a certain amount of continuous flow through the high pressure valve. Any iiow whatsoever through the high pressure valve will, by virtue of the suction eiect of the injector device 52, tend to promote flow through the steam system whenever the low pressure valve 53 is opened in the repeated cycles of rotation of the disc 12.

Sixth mode of operation In the sixth mode of operation the system is set up as described under the i'lrst Inode of operation, but the adjustment screws 81 for controlling the position of the brush 83 is moved to one of its extreme positions or the other to .cause constant energization of one or the other of the solenoids 65 and 1U to permit release of steam solely from one or the other of the valves 51 and 58 in a constant manner. This mode of operation may be used temporarily for some special reason.

Seventh mode of operation In the seventh mode of operation the electrical arrangement for energizing the solenoids 65 and 16 is deenergized so that the positions of the low pressure valve 58 and the high pressure valve 41 will be determined solely by adjustment of the corresponding screws 68 and 62. The adjustment of the two valve controlling screws is such as to permit one or both of the valves to release steam continuously to the surge tank 5I. If both valves are opened the suction eiect created by the injector device 52 will substantially increase the velocity gg ow through the various drier cylinders I9 and It will be readily appreciated that the described arrangement for controlling the release of steam from the high pressure and low pressure sides of a steam heating system, or any other arrangement of the same general character, may be used to supply any steam-consuming device with steam from the heating system with consequent promotion of flow through the heating system. The outside demand may be the requirement of steam to heat water, the requirement of steam for circulation through coils to heat air, et cetera. In the claims the phrase a substantially clear channel is to be taken as meaning a channel providing suicient freedom of communication therethrough to cause velocity responses to the release of steam therefrom.

It is apparent that the invention may be practiced with pulsating intermittent release of steam in which it is contemplated that there will be a complete cessation of steam release between pulsations, and that the'invention may be practiced with pulsating continuous release in which the rate cflow' varies between positive values. In either of these practices the frequency of,.- the conseauent variations in pressure; in. the Steam Will be sufciently high to reap the advantages lowered thermal resistance at the heat exchangers that are explained in the previously mentioned copending Harrison et al. application.

It is also to be noted that the described system in some practices of the invention may operate without substantial or even significant pulsations, the two valves serving solely as means to apportion the derived steam between the two channels.

The description herein in specific detail of a preferred embodiment of the invention will suggest to those skilled in the art various changes and substitutions under the basic concept, and the right is reserved to all such departures from the disclosure that lies within the scope of the appended claims.

I claim as my invention:

1. In a steam system including a steam source, a heat exchanger connected thereto with a substantially clear channel from the steam source through the heat exchanger, and a steam consuming device, the combination therewith of means to create pulsating steam iow through said heat exchanger for increased heat output by the heat exchanger, said means comprising a first passage means from said channel on the low pressure side of the heat exchanger to said device to promote steam flow through the heat exchanger and to satisfy a fraction of the steam demand of the device, a second passage means from said steam source to said device to satisfy the remainder of the steam demand of the device without substantial effect on the steam flow through the heat exchanger, and means controllingr flow through said two passage means in continually repeated cycles of two stages, one stage in which said steam demand is satisfied primarily by said heat exchanger through said first passage means and one stage in which said steam demand is satisfied primarily by said source through the other of said passage means, whereby the velocity of steam flow through said heat exchanger is continually varied in a pulsating manner.

2. In a steam system a combination as set forth in claim l which includes adjustable means to vary the frequency of said cycles, thereby to vary the frequency of the flow pulsations.

3. In steam system a combination as set forth in claim l which includes means to vary the relative durations of said two stages in a cycle.

4. In a steam system a combination as set forth in claim 1 which includes means to vary the magnitude of steam flow in at least one of said passages in at least one of said stages.

5. In a steam system including a steam' source, a heat exchanger connected thereto with a substantially clear channel from the steam source through the heat exchanger, and a steam consuming device, the combination therewith of means to create pulsating steam flow through said heat exchanger for increased heat output by the heat exchanger, said means comprising a rst passage means from said channel on the low pressure side of the heat exchanger to said device to promote steam flow through the heat exchanger and to satisfy a fraction of the steam demand of the device, a second passage m'eans from said steam source to said device to satisfy the; remainder of the. steam demand of the dee vice without substantial effect on the steam flow through the heat exchanger, two valvev means for saidtwo. passage means, respectively, said two valve means being interlocked for opening movement of the two valve means alternately, and means to operate, said, two. valve means repeatedly for milsating` variati-on in the rate of flow through said heat exchanger without corresponding variation in the rate of flow to said device.

6. In a steam system including a steam' source, a heat exchanger connected thereto with a substantially clear channel from the steam source through the heat exchanger, and a steam consuming device, the combination therewith of means to create pulsating steam flow through heat exchanger for increased heat output by the heat exchanger, said means comprising a irst passage means from said channel on the lcw pressure side of the heat exchanger to said device to promote steam ow through the heat exchanger and to satisfy a fraction of the steam demand of the device, a second passage means from said steam source to said device to satisfy the remainder of the steam demand of the device, two passage means cooperating to form an injector' means whereby the flow of steam through said second passage means increases the Velocity of flow through said rst passage means, and means t@ vary the rate of flow through said first passage means in a pulsating manner thereby to continually vary the rate of flow through said heat exchanger in a, pulsating manner.

7. In a steam system' including a steam source, heat exchanger connected thereto with a substantially clear channel from the steam source through the heat exchanger, and a steam consuming device, the combination therewith of means to create pulsating steam flow through said heat exchanger for increased heat output by the heat exchanger, said means comprising a rst passage means from said channel on the low pressure side of the heat exchanger to said device to promote steam flow through the heat exchanger and to satisfy a fraction of the steam demand of the device, a second passage means from' said steam source to said device to satisfy the remainder of the steam demand of the device without substantial effect on the steam ow through the heat exchanger, means controlling flow through said two passage means in repeated cycles of two stages, one stage in which said steam demand is satisfied primarily by one of said passage means and one stage in which said steam demand is satisfied primarily by the other of said passage means whereby the velocity of steam flow through said channel is continually varied in a pulsating manner, and a surge tank in communication with said two passage means to minimize pulsations in the flow of steam to said device.

8. In a steam system having a heat exchanger and a steam consuming device discharging steam into substantially atmospheric pressure the combination therewith of means to supply said device with steam and at the same time to create pulsating fiow in said heat exchanger to attack the gas and condensate films in the heat exchanger, said means comprising a rst passage means to supply steam to said device from the low pressure side of said heat exchanger, thereby to promote flow through the heat exchanger, a second passage means providing communication from another part of the steam system to said device to supply steam to the device, and contnu'aly operating valve means to open and close said two passage means alternately to cause pulsating ow in said heat exchanger Without interruptng the supply of steam to said device.

ELMER PAUL HARRISON.

REFERENCES CITED The following references are of record in the fue of this patent:

Number UNITED STATES PATENTS Name Date Weber May 14, 1889 Reiss et a1 July 31, 1934 Kuester et al. Apr. 4, 1939 Harrison et a1 Jan. 2, 1945 

